This application relates to an environmental control system for an aircraft which taps both high and low pressure compressed air for uses on an aircraft.
Environmental control systems are known, and associated with an aircraft. Typically, these systems tap air from a gas turbine engine on the aircraft, and send it to the aircraft cabin, and other air uses on the aircraft.
The systems typically tap low pressure compressed air from a lower pressure compressor location, and higher pressure compressed air from a higher pressure compressor location. The two are utilized at distinct times during the operation of a gas turbine engine, dependent on the needs, and the available air.
In the prior art, when the higher pressure air is tapped, it is at a very high temperature. Thus, cooling of the air must occur. It is typical that some form of intercooler or other heat exchanger is included.
In addition, the higher pressure compressed air has already been compressed beyond the level of the lower pressure compressed air. The more higher pressure compressed air that is diverted away from engine uses, the lower the efficiency of the engine.